Display panel and display device including the same

ABSTRACT

A display panel is disclosed, which includes: a substrate; plural scan lines disposed on the substrate and extending along a first direction; a first insulating layer disposed on the scan lines; plural data lines disposed on the first insulating layer and extending along a second direction; a second insulating layer disposed on the data lines; and a common electrode disposed on the second insulating layer and including a through hole; wherein, the through hole includes a first region and a second region, the first region has a first maximum width along the first direction, the second region has a second maximum width along the first direction, and a ratio of the second maximum width over the first maximum width is greater than 0 and less than 1.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefits of the Taiwan Patent ApplicationSerial Number 105118112, filed on Jun. 8, 2016, the subject matter ofwhich is incorporated herein by reference.

BACKGROUND 1. Field

The present disclosure relates to a display panel and a display deviceincluding the same and, more particularly, to a display panel that athrough hole of a common electrode has a specific designed shape and adisplay device including the same.

2. Description of Related Art

With the continuous advancement of technologies related to displays, allthe display panels are now developed toward compactness, thinness, andlightness. This trend makes thin displays, such as liquid crystaldisplay panels, organic light-emitting diode display panels andinorganic light-emitting diode display panels, replacingcathode-ray-tube displays as the mainstream display devices on themarket. Applications of thin displays are numerous. Most electronicproducts for daily use, such as mobile phones, notebook computers, videocameras, still cameras, music displays, mobile navigators, and TV sets,employ such display panels.

Among the developed thin displays, LCD display devices particularlyenjoy technical maturity; and manufacturers pay even more effort toimprove display devices in terms of display quality thereby answering toongoing technical development of display devices and consumers'increasing demands.

Therefore, the elements comprised in the display device still have to beimproved, so a display device with higher display quality can beprovided to meet the consumers' increasing demands.

SUMMARY

The display panel of the present disclosure comprises: a substrate;plural scan lines disposed on the substrate, wherein the plural scanlines extend along a first direction; a first insulating layer disposedon the plural scan lines; plural data lines disposed on the firstinsulating layer, wherein the plural data lines extend along a seconddirection, and the first direction is different from the seconddirection; a second insulating layer disposed on the plural data lines;and a common electrode disposed on the second insulating layer, whereinthe common electrode includes a through hole. Herein, the through holeincludes a first region and a second region, the first region includes afirst edge and the second region includes a second edge, the first edgeand the second edge intersect at two inflection points, the first regionhas a first maximum width (W1) along the first direction, the secondregion has a second maximum width (W2) along the first direction, and aratio of the second maximum width over the first maximum width isgreater than 0 and less than 1 (0<W2/W1<1).

The display device of the present disclosure comprises: a substrate; acounter substrate opposite to the substrate; a display medium layerdisposed between the substrate and the counter substrate; plural scanlines disposed on the substrate, wherein the plural scan lines extendalong a first direction; a first insulating layer disposed on the pluralscan lines; plural data lines disposed on the first insulating layer,wherein the plural data lines extend along a second direction, and thefirst direction is different from the second direction; a secondinsulating layer disposed on the plural data lines; and a commonelectrode disposed on the second insulating layer, wherein the commonelectrode includes a through hole. Herein, the through hole includes afirst region and a second region, the first region includes a first edgeand the second region includes a second edge, the first edge and thesecond edge intersect at two inflection points, the first region has afirst maximum width (W1) along the first direction, the second regionhas a second maximum width (W2) along the first direction, and a ratioof the second maximum width over the first maximum width is greater than0 and less than 1 (0<W2/W1<1).

Other novel features of the disclosure will become more apparent fromthe following detailed description when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a display device according to oneembodiment of the present disclosure.

FIGS. 2A to 2C are top views showing elements on a substrate of adisplay device according to one embodiment of the present disclosure.

FIG. 3A is a cross-sectional view at the line A-A′ indicated in FIG. 2B.

FIG. 3B is a cross-sectional view at the line B-B′ indicated in FIG. 2B.

FIG. 3C is a cross-sectional view at the line C-C′ indicated in FIG. 2B.

FIGS. 4A and 4B are partial enlarged views of FIG. 2C.

FIG. 4C is a partial enlarged view of FIG. 2A.

FIG. 5 is a diagram showing a simulation result of a transmittance of adisplay device according to one embodiment of the present disclosure.

FIGS. 6A and 6B are top views showing elements on a substrate of adisplay device according to another embodiment of the presentdisclosure.

FIG. 6C is a partial enlarged view of FIG. 6B.

DETAILED DESCRIPTION OF EMBODIMENT

The following embodiments when read with the accompanying drawings aremade to clearly exhibit the above-mentioned and other technicalcontents, features and effects of the present disclosure. Through theexposition by means of the specific embodiments, people would furtherunderstand the technical means and effects of the present disclosure.Moreover, as the contents disclosed herein should be readily understoodand can be implemented by a person skilled in the art, all equivalentchanges or modifications which do not depart from the concept of thepresent disclosure should be encompassed by the appended claims.

Furthermore, the ordinals recited in the specification and the claimssuch as “first”, “second” and so on are intended only to describe theelements claimed and imply or represent neither that the claimedelements have any proceeding ordinals, nor that sequence between oneclaimed element and another claimed element or between steps of amanufacturing method. The use of these ordinals is merely todifferentiate one claimed element having a certain designation fromanother claimed element having the same designation.

Furthermore, the ordinals recited in the specification and the claimssuch as “above”, “over”, or “on” are intended not only directly contactwith the other substrate or film, but also intended indirectly contactwith the other substrate or film.

Furthermore, the features in different embodiment of the presentdisclosure can be mixed to form another embodiment.

FIG. 1 is a cross-sectional view of a display device according to oneembodiment of the present disclosure. The display device of the presentembodiment comprises: a display panel 11; and a backlight module 12disposed below the display panel 11. The display panel 11 comprises: asubstrate 111; a counter substrate 112 opposite to the substrate1 111and a display medium layer 113 disposed between the substrate 111 andthe counter substrate 112. In the present embodiment, the substrate 111can be a transistor substrate with transistors (not shown in the figure)formed thereon; and the counter substrate 112 can be a color filtersubstrate with a color filter layer (not shown in the figure) and ablack matrix layer (not shown in the figure) formed thereon. However, inother embodiment of the present disclosure, the color filter layer (notshown in the figure) can be disposed on the substrate 111; and in thiscase, the substrate 111 is a color filter on array (COA) substrate.Alternatively, the black matrix layer (not shown in the figure) can bedisposed on the substrate; and in this case, the substrate 111 is ablack matrix on array (BOA) substrate. In addition, the display mediumlayer 113 in the display device of the present disclosure is a liquidcrystal layer. Hereinafter, the features of the elements disposed on thesubstrate 111 are illustrated. It should be noted that “element” in thepresent disclosure is not directed to any particular object but is ageneral term used to indicate any object disposed on the substrate 111.

FIGS. 2A to 2C are top views showing elements on a substrate of adisplay device according to one embodiment of the present disclosure,wherein the difference between FIG. 2A and FIG. 2B is that the hatchinglines of some layers in FIG. 2A are not shown in FIG. 2B forsimplification, and the difference between FIG. 2A and FIG. 2C is thatpixel electrodes are not shown in FIG. 2C to clearly illustrate therelation between through holes of a common electrode and a scan line.FIGS. 3A to 3C are cross-sectional views at the lines A-A′, B-B′ andC-C′ indicated in FIG. 2B. In the present embodiment, a low temperaturepolysilicon (LTPS) transistor substrate is exemplified. However, thepresent disclosure is not limited thereto, and an amorphous transistorsubstrate, an IGZO transistor substrate or other transistor substratescan also be applied in the display device of the present disclosure.

The elements disposed on the substrate can be prepared by any knownprocess in the art. In brief, as shown in FIGS. 3A, 3B and 3C, asubstrate 21 is provided, and a buffer layer 22 is disposed on thesubstrate 21. Next, active layers 23 which are polysilicon layers areformed on the buffer layer 22, followed by forming a gate insulatinglayer 24 on the active layers 23 and the buffer layer 22. Then, a firstmetal layer 25 is formed on the gate insulating layer 24, and the firstmetal layer 25 comprises plural scan lines 251. A first insulating layer26 is formed on the first metal layer 25. Herein, the first insulatinglayer 26 is a double layered insulating layer comprising two insulatinglayers 261, 262, but the present disclosure is not limited thereto.

Next, a second metal layer 27 is formed on the first insulating layer26. The second metal layer 27 comprises plural data lines 271, drainelectrodes 272 and source electrodes 273, wherein the drain electrodes272 and the source electrodes 273 electrically connects to the activelayers 23 through openings 263 of the first insulating layer 26. Asecond insulating layer 28 is formed on the first insulating layer 26and the second metal layer 27. A common electrode 31 is formed on thesecond insulating layer 28. In a top view toward a surface of thesubstrate 21, which means along a direction perpendicular to a surfaceof the substrate 21, the common electrode 31 includes through holes 311.The through holes 311 overlap the drain electrodes 272 and a part of thescan lines 251. Then, a third insulating layer 32 is formed on thecommon electrode 31. Pixel electrodes 33 are formed on the thirdinsulating layer 32, wherein the pixel electrodes 33 electricallyconnect to the drain electrodes 272 through the contact holes 281. Asshown in FIGS. 1 and 3B, the display medium layer 113 can be disposedbetween the counter substrate 112 and the pixel electrodes 33 afterassembling the substrate 21 and the counter substrate 112.

In the display device of the present embodiment, the substrate 21 can beprepared by glass, plastics, flexible materials, thin films or othersubstrate materials. When the substrate 21 is prepared by plastics,flexible materials or thin films, a flexible display device can beobtained. The flexible material can include PI (polyimide), PC(polycarbonate), PET (polyethylene terephthalate), or the like. Thebuffer layer 22, the gate insulating layer 24, the first insulatinglayer 26, the second insulating layer 28 and the third insulating layer32 can be prepared by inorganic insulating materials or organicinsulating materials. The inorganic insulating material can includesilicon oxides, silicon nitrides, silicon oxynitrides, or the like. Theorganic insulating material can include PFA (perfluoroalkoxy resin) orthe like. The first metal layer 25 and the second metal layer 27 can beprepared by conductive materials such as metals, alloys, metal oxides,metal nitroxides or other electrode materials. The common electrode 31and the pixel electrode 33 can be prepared by transparent conductivematerials, for examples ITO, IZO or ITZO. However, in other embodimentof the present disclosure, the materials of the aforesaid elements arenot limited to the examples illustrated before.

As shown in FIGS. 2A and 3A, the display panel of the present embodimentcomprises: a substrate 21; plural scan lines 251 (belonged to the firstmetal layer 25) disposed on the substrate 21, wherein the plural scanlines 251 extend along a first direction X; a first insulating layer 26disposed on the plural scan lines 251; plural data lines 271 (belongedto the second metal layer 27) disposed on the first insulating layer 26,wherein the plural data lines 271 extend along a second direction, andthe first direction X is different from the second direction; a secondinsulating layer 28 disposed on the plural data lines 271; and a commonelectrode 31 disposed on the second insulating layer 28, wherein thecommon electrode 31 includes a through hole 311. Herein, the plural scanlines 251 respectively extend along the first direction X as indicatedin the axis shown in FIG. 2A. The plural data lines 271 respectivelyextend along the second direction, wherein as long as the firstdirection X is different from the second direction, the second directionis not necessarily perpendicular to the first direction X and an anglecan be included between the second direction and the first direction X(for example, an angle of 80-90 degree, or an angle of 85-90 degree).

Hereinafter, the feature of the through hole 311 of the common electrode31 is illustrated in detail.

FIG. 4A is a partial enlarged view of FIG. 2C. In the display panel ofthe present embodiment, the through hole 311 of the common electrode 31includes a first region R1 and a second region R2. In a top view towarda surface of the substrate, the first region R1 overlaps at least one ofthe plural scan lines 251 along a direction perpendicular to the surfaceof the substrate, the second region R2 does not overlap the at least oneof the plural scan lines 251 along a direction perpendicular to thesurface of the substrate. Or, the first region R1 and the second regionR2 are adjacent to each other. The first region R1 has a first edge 311a and the second region R2 has a second edge 311 b. And the first edge311 a and the second edge 311 b intersect at two inflection points P inwhich the first edge 311 a changes from being concave to convex or thesecond edge 311 b changes from being concave to convex. Herein, thefirst edge 311 a refers to an edge of the through hole 311 correspondingto the first region R1, and the second edge 311 b refers to another edgeof the through hole 311 corresponding to the second region R2. In thedisplay panel of the present embodiment, the first region R1 has a firstmaximum width W1 along the first direction X, the second region R2 has asecond maximum width W2 along the first direction. X, and a ratio of thesecond maximum width W2 over the first maximum width W1 (W2/W1) isgreater than 0 and less than 1 (0<W2/W1<1).

In general, the common electrode 31 includes a through hole 311, and apart of the drain electrode 272 is exposed from the through hole 311.Hence, the pixel electrode 33 above the common electrode 31 canelectrically connect to the drain electrode 272. Although the aforesaidpurpose of electrically connecting the pixel electrode 33 and the drainelectrode 272 can also be accomplished when the first maximum width W1of the first region R1 is identical to the second maximum width W2 ofthe second region, a capacitance is formed at the overlapping region ofthe common electrode 31 and the san line 251 (i.e. the first region R1),resulting in the display quality decreased. Hence, in the display panelof the present embodiment, the area of the scan line 251 capable ofexposing from the first region R1 of the through hole 311 is increasedby enlarging the first region R1 (especially, by increasing the firstmaximum width W1 of the first region R1 along the first direction X).Therefore, the area of the overlapping region of the common electrode 31and the scan line 251 can be reduced, so the capacitance formed betweenthe common electrode 31 and the scan line 251 can be decreased and thedisplay quality of the display device can be increased.

In addition, in the display panel of the present embodiment, in a topview toward a surface of the substrate, the common electrode 31 overlapsat least a portion of the plural data lines 271 along a directionperpendicular to the surface of the substrate. More specifically, thethrough hole 311 of the common electrode 31 is located between two ofthe plural data lines 271, and the two of the plural data lines 271 areadjacent to each other. Therefore, the transmittance of the displaydevice can be improved. In particular, in the display panel of thepresent embodiment, one of the plural data lines 271 adjacent to a firstedge 311 a of the first region R1 is defined as a first data line 271 a,a first minimum distance D1 is between the first data line 271 a and thefirst edge 311 a, a second minimum distance D2 is between the first dataline 271 a and a second edge 311 b of the second region R2, and thefirst minimum distance D1 is greater than 0 μm and less than the secondminimum distance D2 (0 μm<D1<D2). In other word, a section of the firstedge 311 a adjacent to the first data line 271 a is defined as a firstsection 311 a′, a section of the second edge 311 b adjacent to the firstdata line 271 a is defined as a second section 311 b′, the first section311 a′ is spaced apart from the first data line 271 a by a first minimumdistance D1, the second section 311 b′ is spaced apart from the firstdata line 271 a by a second minimum distance D2, and the first minimumdistance D1 is less than the second minimum distance D2. In oneembodiment, the first minimum distance D1 is greater than 0 μm and lessthan the second minimum distance D2 (0 μm<D1<D2). If the first minimumdistance D1 is 0 μm, light leakage may be occurred at the area betweenthe common electrode 31 and the data line 271 (i.e. the first data line271 a). Furthermore, in order to decrease the capacitance formed by thecommon electrode 31 and the scan line 251, the first maximum width W1 ofthe first region R1 is greater than the second maximum width W2 of thesecond region R2; therefore, the first minimum distance D1 is less thanthe second minimum distance D2.

The length of the second minimum distance D2 is not particularlylimited, as long as the second region R2 can expose the drain electrode272, so that the pixel electrode 33 can electrically connect to thedrain electrode 272. In one embodiment of the present disclosure, thesecond minimum distance D2 is equal to or greater than 2 μm and lessthan 10 μm. In the present embodiment, a simulation of the transmittanceof the display device is performed by fixing the first minimum distanceD1 to be 2 μm and adjusting the length of the second minimum distanceD2. The simulation result is shown in FIG. 5. As the second minimumdistance D2 increased, the transmittance of the display device isfurther improved. In particular, a better transmittance can be obtainedwhen the second minimum distance D2 increases.

FIG. 4B is a partial enlarged view of FIG. 2C, wherein the differencebetween FIG. 4A and FIG. 4B is only the symbols. As shown in FIG. 4B, inthe display device of the present embodiment, one of the plural scanlines 251 has a third maximum width W3 along the second direction Y, thefirst region R1 has a fourth maximum width W4 along the second directionY, and a ratio of the fourth maximum width W4 over the third maximumwidth W3 is greater than 0.5 and less than or equal to 1 (0.5<W4/W3≦1).Furthermore, the second region R2 has a fifth maximum width W5 along thesecond direction Y, and a ratio of the fifth maximum width W5 over thefourth maximum width W4 is equal to or greater than 1 and less than 4(1≦W5/W4<4).

In addition, as shown in FIG. 4B, the first section 311 a′ of the firstedge 311 a (shown in FIG. 4A) and the second section 311 b′ of thesecond edge 311 b (shown in FIG. 4A) intersects at the inflection pointP, a first line L1 is tangential to the first section 311 a′ at theinflection point P, a second line L2 is tangential to the second section311 b′ at the inflection point P, and the first line L1 and the secondline L2 forms at an angle δ which is equal to or greater than 90 degreeand less than or equal to 180 degree. It should be noted that the angleθ is defined in the figure.

FIG. 4C is a partial enlarged view of FIG. 2A. As shown in FIGS. 3B and4C, the display device of the present embodiment further comprises athird insulating layer 32 and a pixel electrode 33, wherein the thirdinsulating layer 32 is disposed on the common electrode 31, and thepixel electrode 33 is disposed on the third insulating layer 32. In atop view of the display device when observing onto a substrate surfaceof the substrate 21 (more specifically, observing from the pixelelectrode 33 to the substrate 21), the first region R1 at leastpartially overlaps the pixel electrode 33 along a directionperpendicular to the surface of the substrate. In other embodiment ofthe present disclosure, the edge of the pixel electrode may be at leastpartially disposed in the first region R1.

FIGS. 6A and 6B are top views showing elements on a substrate of adisplay device according to another embodiment of the presentdisclosure. The display device of the present embodiment is similar tothat shown in the aforementioned embodiments, and the main difference isthe position of the data lines 271.

FIG. 6C is a partial enlarged view of FIG. 6B. In the presentembodiment, one of the data lines adjacent to a first edge 311 a of thethrough hole 311 is defined as a first data line 271 a, and the firstdata line 271 a is electrically connected to the adjacent pixel, and isnot electrically connected to the pixel that the through hole 311disposed therein. Similar to the embodiments illustrated before, a firstminimum distance D1 is between the first data line 271 a and the firstedge 311 a, a second minimum distance D2 is between the first data line271 a and the second edge 311 b, and the first minimum distance D1 isgreater than 0 μm and less than the second minimum distance D2 (0μm<D1<D2).

Please compare FIG. 4A and FIG. 6C. In the display device of the presentembodiment, the relation between the first minimum distance D1 and thesecond minimum distance D2 is decided by the first edge 311 a of thethrough hole 311 and its closest data line. In other word, the data line271 (i.e. the first data line 271 a) closest to the first edge 311 a canbe the data line of the present pixel (as shown in FIG. 4A) or the dataline of the adjacent pixel (as shown in FIG. 6C).

A display device made as described in any of the embodiments of thepresent disclosure as described previously may be integrated with atouch panel to form a touch display device. Moreover, a display deviceor touch display device made as described in any of the embodiments ofthe present disclosure as described previously may be applied to anyelectronic devices known in the art that need a display screen, such asdisplays, mobile phones, laptops, video cameras, still cameras, musicplayers, mobile navigators, TV sets, and other electronic devices thatdisplay images.

Although the present disclosure has been explained in relation to itsembodiment, it is to be understood that many other possiblemodifications and variations can be made without departing from thespirit and scope of the disclosure as hereinafter claimed.

What is claimed is:
 1. A display panel, comprising: a substrate; pluralscan lines disposed on the substrate, wherein the plural scan linesextend along a first direction; a first insulating layer disposed on theplural scan lines; plural data lines disposed on the first insulatinglayer, wherein the plural data lines extend along a second direction,and the first direction is different from the second direction; a secondinsulating layer disposed on the plural data lines; and a commonelectrode disposed on the second insulating layer, wherein the commonelectrode includes a through hole, wherein the through hole includes afirst region and a second region, the first region includes a first edgeand the second region includes a second edge, the first edge and thesecond edge intersect at two inflection points, the first region has afirst maximum width along the first direction, the second region has asecond maximum width along the first direction, and a ratio of thesecond maximum width over the first maximum width is greater than 0 andless than
 1. 2. The display panel of claim 1, wherein the commonelectrode overlaps at least a portion of the plural data lines along adirection perpendicular to a surface of the substrate.
 3. The displaypanel of claim 1, wherein the through hole is located between two of theplural data lines, and the two of the plural data lines are adjacent toeach other.
 4. The display panel of claim 1, wherein the first regionoverlaps at least a portion of the plural scan lines along a directionperpendicular to a surface of the substrate.
 5. The display panel ofclaim 1, wherein the plural data lines includes a first data line, thefirst edge includes a first section adjacent to the first data line, thesecond edge includes a second section adjacent to the first data line,the first section is spaced apart from the first data line by a firstminimum distance, the second section is spaced apart from the first dataline by a second minimum distance, and the first minimum distance isless than the second minimum distance.
 6. The display panel of claim 5,wherein the second minimum distance is equal to or greater than 2 μm andless than 10 μm.
 7. The display panel of claim 1, wherein a first lineis tangential to the first edge at one of the inflection points, asecond line is tangential to the second edge at the one of theinflection points, and the first line and the second line forms at anangle which is equal to or greater than 90 degree and equal to or lessthan 180 degree.
 8. The display panel of claim 1, wherein one of theplural scan lines has a third maximum width along the second direction,the first region has a fourth maximum width along the second direction,and a ratio of the fourth maximum width over the third maximum width isgreater than 0.5 and less than or equal to
 1. 9. The display panel ofclaim 1, wherein the first region has a fourth maximum width along thesecond direction, the second region has a fifth maximum width along thesecond direction, and a ratio of the fifth maximum width over the fourthmaximum width is equal to or greater than 1 and less than
 4. 10. Thedisplay panel of claim 1, further comprising a third insulating layerand a pixel electrode, wherein the third insulating layer is disposed onthe common electrode, the pixel electrode is disposed on the thirdinsulating layer, and the first region at least partially overlaps thepixel electrode along a direction perpendicular to a surface of thesubstrate.
 11. A display device, comprising: a substrate; a countersubstrate opposite to the substrate; a display medium layer disposedbetween the substrate and the counter substrate; plural scan linesdisposed on the substrate, wherein the plural scan lines extend along afirst direction; a first insulating layer disposed on the plural scanlines; plural data lines disposed on the first insulating layer, whereinthe plural data lines extend along a second direction, and the firstdirection is different from the second direction; a second insulatinglayer disposed on the plural data lines; and a common electrode disposedon the second insulating layer, wherein the common electrode includes athrough hole, wherein the through hole includes a first region and asecond region, the first region includes a first edge and the secondregion includes a second edge, the first edge and the second edgeintersect at two inflection points, the first region has a first maximumwidth along the first direction, the second region has a second maximumwidth along the first direction, and a ratio of the second maximum widthover the first maximum width is greater than 0 and less than
 1. 12. Thedisplay device of claim 11, wherein the common electrode overlaps atleast a portion of the plural data lines along a direction perpendicularto a surface of the substrate.
 13. The display device of claim 11,wherein the through hole is located between two of the plural datalines, and the two of the plural data lines are adjacent to each other.14. The display device of claim 11, wherein the first region overlaps atleast a portion of the plural scan lines along a direction perpendicularto a surface of the substrate.
 15. The display device of claim 11,wherein the plural data lines includes a first data line, the first edgeincludes a first section adjacent to the first data line, the secondedge includes a second section adjacent to the first data line, thefirst section is spaced apart from the first data line by a firstminimum distance, the second section is spaced apart from the first dataline by a second minimum distance, and the first minimum distance isless than the second minimum distance.
 16. The display device of claim15, wherein the second minimum distance is equal to or greater than 2 μmand less than 10 μm.
 17. The display device of claim 11, wherein a firstline is tangential to the first edge at one of the inflection points, asecond line is tangential to the second edge at the one of theinflection points, and the first line and the second line forms at anangle which is equal to or greater than 90 degree and equal to or lessthan 180 degree.
 18. The display device of claim 11, wherein one of theplural scan lines has a third maximum width along the second direction,the first region has a fourth maximum width along the second direction,and a ratio of the fourth maximum width over the third maximum width isgreater than 0.5 and less than or equal to
 1. 19. The display device ofclaim 11, wherein the first region has a fourth maximum width along thesecond direction, the second region has a fifth maximum width along thesecond direction, and a ratio of the fifth maximum width over the fourthmaximum width is equal to or greater than 1 and less than
 4. 20. Thedisplay device of claim 11, further comprising a third insulating layerand a pixel electrode, wherein the third insulating layer is disposed onthe common electrode, the pixel electrode is disposed on the thirdinsulating layer, and the first region at least partially overlaps thepixel electrode along a direction perpendicular to a surface of thesubstrate.